Help! How did this happen? Fantom pro 29er

I'm obviously new to this and I've noticed that i've bent inward a little a couple of teeth on the largest sprocket and there's also a couple of teeth that slightly look like there bent inward on the cassette. On the sprocket it also looks like that when it occurred it also took some of the paint and some of the metal from the tip of the teeth as it bent in . Can someone tell me if i did this by not shifting correctly? Is there something wrong with my bike? What's the proper way to shift a bike. For example is it imperative that i go from the next gear up slowly one at a time and so on with the sprocket gears. I would really appreciate any and all suggestions and advice.

Bent teeth on the big chainwheel can come from hitting it on logs. But bent teeth on the cassette are a little odd. Doubtful that it was caused by anything you did, it is more likely they came that way. Poor shifting technique can quickly wear down the teeth, but to bend them you would need some serious leg power. Especially since you say they are bent inward, the teeth on the cassette and rings are not really even loaded in that direction, so it would be close to impossible for you to have bent them from just pedaling. I guess if you wrecked and the cassette hit a rock that would do it.

As far as shifting technique, you want to do your best not to shift under load. You want your shifts to be as smooth as possible. If you need to shift on a hill you need to learn to ease up on the pedals right as you shift, and then ease back into it until the chain has completely moved. Clanks and pops while shifiting are not normal.